#!/usr/bin/env node

const { Readable } = require('stream');
// =
// const Readable = require('stream').Readable;

const rs = new Readable();
let c = 'a'.charCodeAt(0);

rs._read = () =>{
  rs.push(String.fromCharCode(c++));
  if(c === 'z'.charCodeAt(0)+1)
     rs.push(null);
}

rs.pipe(process.stdout);
